1. Technical Field of the Invention
This invention relates to a cooling device for a motorcycle. More particularly, this invention relates to an improved radiator grille structure for a motorcycle.
2. Description of Related Art
Japanese Patent Laid-open No. Hei 5-69756 is an example of a conventional cooling device for a motorcycle in which a pair of right and left radiators are separately provided behind a front fender. The radiators are provided on both sides of a front tube member and extend in a backward and downward direction.
Japanese patent '756 also shows a conventional radiator grille structure including a plurality of vertically long louvers that are provided in front of the radiators. These louvers are inwardly inclined. Furthermore, the inwardly inclined inclination angle is the same for each louver.
Neither radiator nor radiator grille are provided near the body center line in conventional grille structures such as the '756 patent. As shown in the side view of the '756 patent, the front fender is positioned wholly in front of the radiator grille so as not to interfere with the grille.
Conventionally, a space is required between the rear of the front fender and the radiator grille so that the radiator grille does not interfere the front fender when the front fender is rotated along with the front wheel during a turn. This space increases the wheel base of the motorcycle.
If a single-piece (monolithic) radiator is utilized to cool the motorcycle, then the wheel base must also be increased to accommodate the radiator and grille. Such conventional, single-piece radiators are typically supported between right and left front tube members and have a monolithic structure in the width direction. Because of the monolithic structure, the center portion of the radiator could interfere with the rear of the front fender. To avoid this interference, the wheel base is typically increased to provide a clearance space. Furthermore, if a radiator grille is provided, the wheel base must be further increased to prevent interference between the rear of the front fender and the radiator grille.
Such increases in wheel base are undesirable. A long wheel base reduces the agility and maneuverability of the motorcycle and generally increases the overall weight.